Preheat oven to 180°C.
In a large frying pan heat both oils, add chicken, saute over high heat until golden, about 8 minutes, turning once Remove from pan, season to taste.
Pour fat from frying pan, add half the Calvados and all the vinegar.
Brig to the boil, scraping up any browned bits from the bottom.
Remove from the heat.
Place apples in a casserole, arrange chicken on top.
Pour liquid in the frying pan over chicken, bake for 20 minutes or until chicken is cooked.
Remove chicken from casserole, keep warm.
Pour apples and juices from pan into a food processor or blender, puree.
Pour into a saucepan, add stock and remaining Calvados.
Bring to the boil, cook until sauce thickens, about 5 minutes.
Divide sauce between 4 heated plates, arrange chicken on top.